Valve control for gas lift



Aug. 21, 1956 F. w. BUBB 2,759,429

VALVE CONTROL FOR GAS LIFT Filed June ll, A1951 2 Sheets-Sheet l A T TOPNE V5 Aug. 21, 1956 Filed June ll, 1951.

F. W. BUBB VALVE CONTROL FOR GAS LIFT 2 Sheets-Sheet 2 .Illu- To DowNHoLE APPARATUS F. W. BUBB BY #WO1/rm W A T TOPNEKS United States Patent C VALVE CONTROL FCR GAS LIFT Frank W. Bubb, St. Louis, Mo., assignor to Phillips Petroleum Company, a corporation of Delaware Application June 11, 1951, Serial No. 230,973

12 Claims. (Cl. 10S-233) This invention relates to producing oil from wells `by a gas lift system. In one specific aspect, it relates to a system wherein any desired one or more of a plurality of electrically-controlled gas lift valves is selected and operated as desired. ln another specific aspect, it relates to a relay circuit of novel design permitting the selection of a predetermined operating circuit in a simple and efficacious manner.

Gas lift devices are particularly advantageous in producing wells where there is a high level of oil between the tubing and casing, or where the oil to ybe produced contains sand or other abrasive material. In the iirst case, the fluid pressure conditions in the well permit eicient and advantageous use of a gas lift system and, in the second case, the presence of sand or abrasive material quickly wears away the parts of sucker rod pumps, necessitating frequent repair and replacement thereof.

Assuming that there is a high uid level in the space between the tubing and casing of a well, and that a series of gas lift valves is disposed along the tubing, gas is admitted to the space between the tubing and casing until the fluid level falls below the first gas lift valve. Thereupon, this valve is opened and gas flows therethrough into the tubing, thereby aerating the oil and causing it to rise to the surface. As the oil level between the casing and tubing drops below the second valve in the series, the uppermost valve is closed and the second valve is opened, operation being continued in this manner with one valve in the system open and the others closed. In a second important method of operating, when the level drops below a valve, such valve is opened and the one above it is gradually closed in a stepwise fashion. Other methods of operation involve the opening and closing of any one or more of the gas lift valves depending upon the conditions under which the well is producing.

The system of this invention permits the desired selection of one or more valves and, in some embodiments, it permits the size of each valve opening to be regulated as desired -from the surface to maintain the optimum operating conditions.

lt is an object of this invention to provide a readily controlled system for selecting and operating one or more of a plurality of gas lift valves in a pumping system for an oil well.

It is a further object to provide a relay circuit of novel function which has wide application in control systems.

It is a still further object to provide a circuit which is simple in construction, reliable in operation, and which utilizes a minimum number of standard circuit components.

Various other objects, advantages and features of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

Figure l is a vertical sectional view of a producing well utilizing the novel gas lift system, showing the valves and their respective control units.

Figure 2 is a detailed view of one of the valves of Figure l.

Figure 3 is a block diagram of the downhole portion of the control circuit.

Figure 4 is a schematic circuit diagram of one of the relay units in the operating state.

Figure 5 is a schematic circuit diagram of one of the relay units in its non-operating state.

Figures 6 to 9, inclusive, are schematic circuit diagrams of various modications of the uphole portion of the circuit; and

Figure l0 is `a top View, partially broken away, of a suitable impulsing device for use with the circuits of Figures 6 to 9, inclusive.

Referring now to the drawings in detail, and particularly to Figure l, I have shown gas lift apparatus for a producing well which includes a casing 11, and a tubing string 12 mounted concentrically therewith, the casing having a perforated portion 13 at the region of engagement with the producing zone 14. Just above the producing zone, a plug 15 is disposed in the interspace between the tubing and casing. As a result, oil ows through the perforated portion 13 of the casing, through one of a plurality of openings 16 in the tubing and, thence, upwardly through the well whence it is discharged from the top portion 1'7 of the tubing. At the top of the well, the interspace -between the tubing and casing is sealed by a cap 18, and fluid under pressure is introduced into this interspace through a conduit 19.

A series of solenoid operated valves 20 are spaced vertically along the tubing. In the example shown, there are four such valves but it will be understood that more or less may be used, as desired, depending upon the pressure conditions of the reservoir, the depth of the well, and various other factors well known to those skilled in the art. superimposed upon and associated with each valve 2i) is a relay or control unit 21 which is secured to the tubing, as by a bracket 22. An electrical conductor connects each adjacent pair of relay units, this conductor being carried within a cable 23 which extends through the upper cap 18 to a windlass 24. In a preferred embodiment of the invention, the cable 23 carries only a single conductor to which connection is made by a slip ring 2S carried by windlass 24, the slip ring being connected by a lead 26 to a switchboard 27 containing the uphole portion of the circuit. The return path for the relay unit circuits extends through the tubing 12 and, accordingly, a conductor 28 connects the tubing with the electrical circuits contained within the switchboard unit 27. Mounted upon the face of switchboard 27 are suitable controls, such as an impulsing dial 29, a meter 30, and switches 31, 32 and 33.

Also associated with the switchboard 27 are a battery 3d of high voltage and a battery 35 of low voltage which are connected to the switchboard circuits by suitable wires.

The detailed construction of the valve units 20 is shown by Figure 2, and each such unit incorporates a housing 37 having a passage 38 formed therein which communicafes with the interspace between the tubing and casing through openings 39. Passage 38 also communicates with a passage d@ defined by a cylindrical valve seat 41 screw threaded within the lower portion of the housing 37. The passage 40 communicates with a pipe 42, Figure l, leading to the interior of the tubing 12. A plunger 4.3 is mounted for reciprocatory movement within an insert 44 carried by and screw threaded to the interior of the housing 37, this plunger being provided with an annular sealing gasket 45. A valve head 46 is disposed at the lower end of plunger 43 and this valve head is urged into engagement with valve seat 41 by a helical spring 47.

Plunger 43, which is formed from magnetic material, extends into an annular solenoid coil 48 which is mounted in abutting relation to the insert 44 and relay unit 21 by a cap 49 screw threaded at the top of the housing 37. One lead of the solenoid coil-relay unit is grounded through housing 37 to the tubing 12 and other terminals are connected to wires 50 extending outwardly through the casing 37 through a sealing member 51 for connectron to cable 23.

When solenoid coil 4S is energized, valve head 46 moves upwardly out of engagement with valve seat 4l, thus permitting gas under pressure to pass through opening 40 into the tubing from the interspace between the tubing and casing. When the solenoid coil is deenergized, the valve head 46 is urged into engagement with valve seat 41 by the spring 47, thereby cutting off the flow of gas just described. This controlled oW of gas is utilized to decrease the specic gravity of the oil passing upwardly through the tubing and to cause an upward tlow of oil through the tubing in a well understood manner. In order to properly control the gas lift operation, it is necessary that any desired valve may be selected and operated at any desired time. It is a major purpose of this invention to provide a reliable and eiective means for controlling the selection and operation of any desired one of the valves 20 at any required time.

In one embodiment of the invention, a ratchet type solenoid valve is used instead of the valve of Figure 2, which is either fully open or fully closed depending on whether or not the solenoid coil 48 is energized. Such a ratchet type valve is operated in a stepwise manner to open the valve by increments as successive electrical control impulses are applied thereto. When the valve reaches its fully open position, the next succeeding current impulse causes it to return to a fully closed position and momentarily closes a set of electrical contacts which change the resistance of the solenoid circuit. Such a change in resistance can be detected uphole by a suitable meter so as to indicate when the valve has been moved to its closed position. A ratchet type valve of the kind just described is shown by Figures 9 to 13, inclusive, of the copending application of R. A. Bobo, Serial No. 77,752, entitled Electro-Mechanical Gas Lift Valve and Control System Therefor, now Patent No. 2,703,532. Such a valve, of course, permits the quantity of gas' flow to be accurately regulated at each valve station, and is very advantageous in certain types of wells.

In the block diagram of Figure 3, I have indicated the downhole circuit of the relay units and solenoid valves. In this block diagram, I have shown a series of ve solenoid valves a to 20e, inclusive, with which are associated, respectively, a series of tive relay units 21a to 21e, inclusive. Relay unit 21a is the top one of the series and is connected through windlass 24 to the uphole circuit at switchboard unit 27, this connection being illustrated by a conductor 54. Further, each relay unit of the series, except the bottom one, is connected to the next lower relay unit by one of a group of conductors 55a to 55d, inclusive, it being understood that the lower portion of conductor 54 and the conductors S5 are positioned within the cable 23, Figure l. The ground connection associated with conductor 28 represents the connection of this conductor to the tubing while the ground connections 56a to 56e, inclusive, represent the connection of various circuit elements toground through the housing 37 and metal member 21 or 42 to the tubing.

In accordance with the invention, any selected relay unit is actuated by feeding a predetermined number of high voltage pulses of short duration to conductor 54. The solenoid valve associated with the selected relay unit is then operated by feeding low voltage current impulses, which may be either of short or long duration, down the line, the voltage of these impulses being too low to actuate the relay units. This permits the use of one conductor connecting the surface to the uppermost valve-relay unit. Each relay unit 21 has an operating state and a nonoperating state, the unit being changed from one state to the other at the application of each high voltage pulse thereto. Further, the circuit of the relay units is such that only each second high voltage pulse is transmitted by any selected relay unit to the next lower relay unit in the series.

Assuming that all of the relay units are in the operating state, the first valve 29a is thereby selected for operation, the line circuit being broken at the rst relay which is in the operating state. Low voltage impulses fed to conductor 54 will then cause operation of valve 20a only, the voltage being too low to operate relay unit 21a. The first high voltage pulse transmitted to conductor 54 will cause unit 21a to assume the non-operating state but this pulse will not be transmitted to unit 2lb, As a result, solenoid valve Ztlb, which is now associated with the uppermost relay in the operating state, is prepared for operation and can be operated by application of low voltage impulses to the line. A second high voltage pulse restores unit 21a to the operating state and this second pulse is transmitted to unit 2lb, causing it to assume the non-operating state, whereupon a third pulse places unit 21a in the non-operating state, this third pulse not being transmitted to unit 2lb or the units below it. This' prepares valve 20c for operation since units 21a, 2lb are now in the non-operating state, and unit 21a` is now the rst one in the operating state. It will be evident, therefore, that a series of three pulses will cause unit 21c to become the first one in the operating state and prepare valve 20c for operation, a series of seven pulses will cause relay unit 21a to become the rst one in the operating state and prepare valve 20d for operation, and a series of fifteen pulses will cause relay unit 21e to become the first one in the operating state and prepare valve 20e for operation. The thirty-second pulse will restore the original condition, with all relays in the operating state.

If a record is kept, a suitable number of pulses can be sent down the line to change the system from any state which may exist to any other desired state. For

- example, if relay unit 21c and all subsequent ones are in the operating state and all preceding relays are in the non-operating state, four additional pulses will prepare valve 20d for operation, twelve additional pulses will prepare valve 20e for operation and twenty-nine additional pulses will prepare valve 20a for operation.

Alternatively and preferably, the system is cleared after each valve actuation. That is, means is provided to bring the system to a standard known condition, for example, one in which all relay units are in the non-operating state, before a valve is selected for operation. The manner of accomplishing this result will become apparent from the following detailed description.

In Figures 4 and 5, I have illustrated one suitable form of relay unit for use in the circuit illustrated by the block diagram of Figure 3. This unit includes a pivoted armature 57 having a set 58, 59 of normally closed contacts and a set 60, 61 of normally open contacts. An electromagnetic means for moving the armature is provided which includes an operating coil 62 to attract the armature and move it into engagement with contacts 60, 61 together with a second coil 63. When the armature moves into the last-described position, it is engaged by a latch 64 which maintains it in its attracted position, the latch being released upon energization of winding 63 with resultant movement of the armature back into engagement with the contacts 58, 59. An auxiliary latch-releasing coil 65 is provided in one embodiment of the invention, one terminal of this coil being grounded and the other being connected to a bind ing post 66.

Contact 58 is connected by a lead 67 to the energizing winding of solenoid valve 43, or other operating circuit when the system is rsed in other than gas lift applications. Contact 59 is connected by a lead 68 to one terminal of operating winding 62, the other terminal of the Winding being grounded. Contact 60 is connected by a lead 69 to one terminal of winding 63, the other terminal of this winding being grounded. Assuming, for purposes of description, that the relay unit illustrated is unit 2lb, the armature is connected to lead 55a while contact 6l is connected to lead 55]). On the last relay of the series, no connection is made to contact 61.

In Figure 4, the relay unit is in the operating state while, in Figure 5, it is in the non-operating state. When the operating state, a low voltage current impulse applied to the line through conductor 55a passes through the armature 57, contact 58, conductor 67, and solenoid winding 48 to actuate the solenoid valve, it being understood that such low voltage impulses are not of suiiicient magnitude as to energize operating coil 62. In the embodiment shown, the low voltage impulse continues throughout the period of Valve operation. Alternatively, the solenoid may be provided with a latch so that it is operated by a iirst impulse, of relatively short duration and restored by a second such impulse. It will be noted that the line circuit is broken by the first relay which is in the operating state. Thus, in Figure 4, contact 61 is open and no voltage is applied through conductor SSb to the rest of the relay units in the series. In a gas lift system, therefore, that valve is selected for operation which is associated with the first relay unit in the operating state, the valve being operated by low voltage impulses, as already described.

When a high voltage pulse is applied to the line through conductor 55a, operating winding 62 is energized, with the result that the armature 57 is attracted thereby and latched in the position shown by Figure 5. The high voltage pulse should be short enough that it terminates before the relay armature engages contact 60 or 61 and before solenoid 48 can operate. As a result, this rst high voltage pulse is not transmitted through contact 61 and conductor SSb to the rest of the relay units in the series.

With the relay in the non-operating state, as shown by Figure 5, low voltage valve-controlling impulses are passed down the line through the non-operating relay units. Thus, in Figure 5, a low voltage impulse impressed upon conductor 55a passes directly through armature 57, contact 61, and conductor 55h to the next lower relay unit in the series, it being understood that such low voltage impulse is not of suicient magnitude as to operate release coil 63. When a high voltage pulse is impressed upon conductor 55a, it is transmitted to the next relay in the series through conductor 55h. Furthermore, such a high voltage pulse actuates winding 63, causing the latch 64 to be released and allowing the armature to return to the position shown in Figure 4. That is, the relay is returned to the operating state.

Accordingly, the operation of the individual relay units may be summarized as follows. Each high voltage pulse causes the relay unit to change state, that is, to change from the operating to the non-operating state or vice versa. Each second pulse is transmitted down the line to the next relay in the series, such transmission of a high voltage pulse occurring when the relay is in the nonoperating state. Finally, low voltage valve-actuating impulses are passed down the line to the rst relay unit which is in the operating state, and no further. Such low voltage impulses pass to the operating circuit of the iirst unit in the operating state, such as the operating circuit of solenoid valve b.

Referring now to Figure 6, I have shown an uphole circuit for controlling the operation of the relay-solenoid valve units shown in Figures 3, 4 and 5. The pulses produced by this circuit are impressed between the con- 6 ductors 28 and 53, Figures 3 and 6. The circuit includes three current sources, such as batteries 70, 71 and 72. One terminal of battery 70 is grounded while the other terminal is connected to battery 71 and through a meter 73, switch 74, and conductor 75 to the line 54. One terminal of battery 71 is connected as aforesaid, the other terminal being connected to battery 72, and through a switch 76 and conductor 77 to the line 54. One terminal of battery 72 is connected as aforesaid, and the other terminal is connected through a switch 78 and a conductor 79 to the line 54.

It will be evident that closure switch 74 causes a low voltage impulse pass down the line 54, closure of switch 76 causes an intermediate voltage to be impressed upon the line, and momentary closure of switch 78 causes a high voltage pulse to be impressed upon the line. When utilizing the uphole circuit shown in Figure 6, the relay windings, Figures 4 and 5, are so designed that the windings 62 are energized by the intermediate voltage appearing at conductor 77 while the windings 63 are not energized by such intermediate voltage. Of course, the low voltage appearing at conductor 75 is of insuliicient strength to energize either of the windings while the high voltage pulses appearing at conductor 79 are capable of energizing any of the windings 62 or 63. Further, switch 78 is of the impulsing type, such as that hereinafter described in connection with Figure l0.

The operation of the circuit is as follows. A series, consisting of a predetermined number of high voltage pulses, is impressed upon line 54 through conductor 79 by an appropriate number of momentary closures of impulsing switch 78. As a result, a preselected relay unit is placed in the operating state with all relay units preceding the preselected one being in the non-operatnig state. Thereupon, switch '74 is actuated as desired to pass low voltage solenoid-operating impulses through conductor 75 to the line S4. Where the valve units are of the type illustrated in Figure 2, closure of switch 74 causes the solenoid of the preselected valve to be energized with resultant opening of the valve and passage of gas under pressure to the tubing at the preselected valve station. Where the valve is of the ratchet type shown in the previously identified application of R. A. Bobo, switch 74 is momentarily actuated a predetermined number of times, each actuation producing a low voltage impulse of relatively short duration which moves the ratchet valve one step toward its open position. As previously stated, such a valve is provided with a set of contacts which are momentarily closed when the valve returns to closed position, thereby producing a momentary change in resistance of the valve circuit with a resultant deiiection of meter 7.3. Thus, the valve can be returned to closed position at any desired time by actuating switch 74 until a momentary meter deflection is noted. Since the number of steps of the ratchet valve is known, it can be opened to the desired extent by thereafter producing a predetermined number of low voltage impulses through actuation of switch 74. Further, all the valve can be opened to any desired extent by successively selecting each of the valves and supplying a desired number of low voltage impulses thereto.

Switch 76 is utilized to restore all of the relay units to their operating state so as to provide an index condition wherein the state of the system is definitely known. The system can then be caused to assume any other desired state by suitable actuation of impulsing switch 78. Closure of switch 76 applies an intermediate voltage to the line 54 through conductor 77 which passes down the line until it reaches the rst relay which is in the operating state. Winding 62 of this relay is energized, with the result that the unit assumes the non-operating state and the armature is latched by member 64. The intermediate voltage is then applied to and latches the next succeeding relay unit which is in the operating state, this operation continuing until each unit assumes the nonoperating state. In this manner, I have provided a method of clearing the system, that is, causing it to assume a predetermined or reference condition.

In Figure 7, I have shown a modied form of uphole circuit, components corresponding to those of Figure 6 being indicated by like reference numerals. This circuit incorporates two batteries 80 and 81, one terminal of battery 80 being connected to ground lead 28, the other terminal being connected to battery 81, and to the low voltage impulsing circuit consisting of meter 73, switch 74 and conductor 75. One terminal of battery 81 is connected as just described, its other terminal being connected to the high voltage pulsing circuit through switch 78 and to a conductor 82 through the switch 76. Conductor 82 is connected to the binding post 66 on each relay unit and is incorporated in the cable 23, Figure 1.

The operation of the low voltage and high voltage irnpulsing circuits controlled by switches 74 and 78, respectively, is the same as explained in connection with Figure 6 and need not be further described. When switch 76 is actuated, the system is restored to a reference condition wherein all the relay units are in the operating state. After such a condition is obtained, any desired valve may be selected for operation by appropriate actuation of impulsing switch 7S. It will be evident that closure of switch 76 energizes the auxiliary winding 65 of each relay unit, thereby releasing each latch 64 and permitting the relay armature to move to their operating position.

In Figure 8, I have shown an uphole circuit which is quite similar to that shown in Figure 7, corresponding parts being indicated by like reference characters. The circuit differs from that of Figure 7 in that the restoring switch 76 and conductors 77, 32 are not utilized, a meter 83 being inserted in the high voltage pulsing circuit in series with switch 78. When using this circuit, a record is ordinarily kept of the condition of the Isystem at all times so that it can be changed from one state to another by sending an appropriate number of high voltage pulses down the line 54. It is possible, however, by the use of meter 83 to determine when the system reaches a condition wherein all of the relay units are in the non-operating state. When this condition occurs, the coil 63 of each relay unit is connected between the line and ground. The impedance of these coils, however, is very high as compared to that of the solenoid coils 48, at least one of which is connected between the line and ground when one or more relay units is in the operating state. Consequently, the current tiow is substantially less when all relay units are in the non-operating -state than at any other time. Thus, impulsing switch 78 can be recurrently actuated until a minimum reading is obtained on ammeter 83, this minimum reading indicating that all relay units are in the non-operating state. In this manner, it is possible to determine when the system is in the referen condition.

In Figure 9, I have shown a niodied uphole circuit which is quite similar to that of Figure 8, like parts being indicated by similar reference characters. In this circuit, the high voltage pulsing circuit is supplied from an individual battery or current source 84. The low voltage impu'lsing circuit includes a battery 85 or other source of low voltage which `is connected in series with a timer 86, the resultant series circuit being connectable through a reversing switch 87 to the line circuit defined by conductors 28 and 54. This circuit permits the delivery of timed low voltage impulses of either polarity to the line circuit, which is a desirable feature when a motor-operated valve is utilized. With such a valve, the direction of motor rotation and, therefore, the determination of whether the valve opens or closes, results from the positioning of reversing switch 37, The length of the current impulse and, hence, the extent of the opening or closing movement of the valve, is determined by the timer 86.

In Figure l0, I have illustrated a suitable impulsing switch for use in the circuits of Figures 6 to 9, inclusive.

This switch includes a. casing 88 upon which are mounted the low voltage impulsing switch 74 and the clearing switch 76 in those embodiments where said switches are utilized. The casing 88 also carries high voltage pulsing switch 78 which incorporates a dial 89, similar to a telephone dial, carried by a rotatable shaft 90, this dial being biased to the rest position shown by a spring 91, and having associated therewith a finger stop 92. Fixed to the shaft 90 is a ratchet wheel 93 having a cooperating7 pawl 94 pivoted at 95 upon a second ratchet wheel 96 which is frictionally mounted upon the shaft 90. It will be noted that the teeth in the two ratchet wheels face in opposite directions and that the teeth occupy arcs of equal angles upon the two ratchet wheels. Cooperating with ratchet wheel 76 is a pawl 97 pivoted at 93 to the casing 88, this pawl having a Contact arm 99 formed integrally therewith. A contact 100 carried by contact arm 99 cooperates with a xed contact 101 carried by a contact spring 102 which is fixed to the casing at 1133. Leads 104, 105 are provided to connect the contacts in any of the circuits shown by Figures 6 to 9, inclusive.

If, for example, four closures of contacts 100, 101 are to be produced, dial 89 is rotated four steps in a clockwise direction, Figure lO, with the result that ratchet wheel 93 advances four steps. This does not produce any rotation of ratchet wheel 96 since pawl 94 slips past the teeth in this ratchet wheel. When the dial is released, it is returned to its rest position by spring 91 and, as a result, ratchet wheel 93 rotates four steps in a counterclockwise direction. Due to the action of pawl 94, ratchet wheel 96 also rotates four steps in a counterclockwise direction with the result that contacts 160, 191 are momentarily closed four times. A similar action, of course, occurs when any other number of impulses is to be produced.

When using the uphole circuit of Figure 7, the system is returned to its index position at which all relay units are in the non-operating state before any desired valve is selected for operation. Thereupon, to select any one of valves number l to 5 for operation, l, 2, 4, 8 or 16 impulses, respectively, must be produced. The dial is, accordingly, provided with guide holes 106 which are spaced at intervals of l, 2, 4, 8 and 16 units, respectively, around the dial, each hole being provided with a guide number corresponding to that of the valve to be selected.

When using the uphole circuit of Figure 6, tlic index position occurs when all the valves are in the operating state. In this index condition, therefore, valve number l is selected for operation. Thereupon, to operate any of valves 2 to 5, inclusive, 1, 3, 7 or l5 impulses, respectively, must be applied to the system. In such case, the guide holes and index numbers are suitably arranged to permit this action to occur when the numbers of the preselected valves are dialed. When using the uphole circuits of Figures 8 and 9, there is no clearing switch 76, and it may be desirable to send any number, from l to 16, of high voltage pulses down the line. In such a case, the dial 89 is provided with an index hole for each number from l to 16 corresponding to the desired number of control pulses.

It will be evident that I have provided a complete and adequate system for selecting and operating any one of a number of gas lift valves, or other mechanisms. The system is very reliable, and can be readily operated by relatively untrained personnel since chances for error are substantially eliminated by the automatic features of the system. Further, the provision of means for attaining a desired index condition assures complete reliability in the selection and operation of any desired valve.

lWhile the invention has been described in connection with a present, preferred embodiment thereof, it is to be understood that this invention is illustrative only and is not intended to limit the invention, the scope of which is dened by the appended claims.

I claim:

l. The combination, tubing mounted concen means for with casing disposed in a well, u trically within said casing, and admitting fluid under pressure to the interspace between said tubing and said casing, of a series of solenoid valves spaced vertically along said tubing, each valve connecting the interior of the tubing with the exterior thereof to regulate the flow of fluid from said interspace into said tubing, and each valve being solenoid loperr ated, a series of relays, one for each valve, each relay including an armature, a set of normally closed contacts and a set ot normally open contacts associated with said armature, an operating winding for attracting said armature to `move it to the non-operating position, a latch for holding said armature in its non-operating position, and a second winding for releasing said latch, said tubing constituting a ground connection for the electrical circuit of said relays, a conductor extending from the top of said Well to the armature of the top relay, a conductor :connecting a normally open contact of each relay with the armature of the next lower relay in said series, a lead connecting a normally closed relay contact to ground through said operating winding, a lead connecting a normally open relay contact to ground through said second winding, and a lead connecting a normally closed relay contact to ground through the solenoid of the associated valve, means for supplying a predetermined number of high voltage relayoperating electrical pulses to the top conductor, to cause a preselected relay to move to its operating position, and thereby prepare a preselected valve for operation, and means for :supplying low voltage solenoid-operating voltage to -said top conductor to eiect operation of the preselected valve.

2. The combination, with casing disposed in a well, tubing mounted concentrically within said casing, and means for admitting lluid under pressure to the interspace between said tubing and said casing, of a series of solenoid valves spaced vertically along said tubing, each valve connecting the interior of the tubing with the exterior thereof to regulate the ilow of fluid from said interspace into said tubing, and each valve being solenoid operated, a series of relays, one for each valve, each relay including an armature, a set of normally closed contacts and a set of normally open contacts associated with said armature, an operating winding for attracting said armature to move it to a non-operating position, a latch for holding said armature in its non-operating position, and a second winding for releasing said latch, said tubing constituting a ground connection for the electrical circuit of said relays, a conductor extending from the top of said well to the armature of the top relay, a conductor connecting a normally open contact of each relay with the armature of the next lower relay in said series, a lead connecting a normally closed relay contact to ground through said operating winding, a lead connecting a normally open relay contact to ground through said second winding, and a lead connecting a normally closed relay contact to ground through the solenoid of the associated valve, means for supplying a predetermined number of high voltage relay-operating electrical pulses to the top conductor, thereby to cause a preselected relay to move to its operating position, thus preparing a preselected valve for operation, means for ysupplying low voltage solenoidoperating voltage to said top conductor to eiect operation of the preselected Valve, and means for supplying an intermediate voltage to said top conductor, said intermediate voltage being of sutiicient magnitude as to operate the second winding of said relays but not of lsufficient magnitude as to actuate the operating winding of said relays.

3. The combination, with casing disposed in a well, tubing mounted concentrically within said casing, and means for admitting iluid under pressure to the interspace between said tubing and said casing, of a series of solenoid valves spaced vertically along said tubing, each valve connecting the interior of the tubing with the exterior thereof to regulate the flow of Huid from said interspace into said tubing, and each valve being solenoid operated,a series of relays, one for each Valve, each relay including an armature, a set of normally closed contacts and a :set of normally open contacts associated with said armature, an operating winding for attracting said armature to move it to a non-operating position, a latch for holding said armature in its non-operating position, and a second winding for releasing said latch, said tubing constituting a ground connection for the electrical circuit of. said relays, a conductor extending from the top of said well to the armature of the top relay, a conductor connecting a normally o-pen contact of each relay with the armature of the next lower relay in said series, a lead connecting a normally closed relay contact to ground through said operating winding, a lead connecting a normally open relay contact to ground through -said second winding, and a lead connecting a normally closed relay contact to ground through the solenoid of the associated valve, means for supplying a predetermined number oi` high Voltage relay-operating electrical pulses to the top conductor, thereby to cause a preselected relay to move to its operating position, mean-s for supplying low-voltage solenoid-operating voltage to said top conductor to effect `operation of the predetermined valve, a wire extending from the top of the well to each of the relays, means for supplying an operating voltage to said wire, and an auxiliary latch-operating winding for each relay having one terminal grounded and its other terminal connected to said wire.

4. The combination, with casing disposed in a well, tubing mounted concentrically within said casing, and means for admitting fluid under pressure to the interspace between said tubing and said casing, of a series of solenoid valves spaced vertically along said tubing, each valve connecting the interior of the tubing with the exterior thereof to regulate the tlow of iluid from said interspace into said tubing, a series of relays, one for each valve, each relay including an armature, a set of normally closed contacts and a set of normally open contacts associated with :said armature, an operating winding for attracting said armature to move it to a non-operating position, a latch for holding said armature in its non-operating position, and a second winding for releasing said latch, said tubing constituting a ground connection for the electrical circuit of said relays, a conductor extending from the top of said well to the armature of the top relay, a conductor connecting a normally open contact of each relay with the armature of the next lower relay in said series, a lead connecting a normally closed relay contact to ground through said operating winding, a lead connecting a normally open relay contact to ground through said second winding, and a lead connecting a normally closed relay contact to ground through the solenoid of the associated valve, a circuit for supplying a predetermined number of high voltage relay-operating electrical pulses to the top conductor, thereby to cause a preseletced relay to move to its operating position, an ammeter connected in said circuit, a low voltage source, a timer connected in circuit therewith, a reversing switch, and leads connecting the low voltage timer circuit through said reversing switch to the circuit deiined by ground and said top conductor.

5. rl`he combination, with casing disposed in a well, tubing mounted concentrically within said casing, and means for admitting fluid under pressure to the interspace between said tubing and said casing, of a series of solenoid valves spaced vertically along said tubing, each valve connecting the interior of the tubing with the exterior thereof to regulate the ilow of iluid from said interspace into said tubing, and each valve being solenoid operated, a series of relays, one for each valve, each relay including an armature, a set of normally closed contacts and a :set of normally open contacts associated with said armature, an operating winding for attracting said armature to move it to a non-operating position, a latch for holding said armature in its non-'operating position, and a second winding for releasing said latch, said tubing constituting a ground connection for the electrica-l circuit of said relays, a conductor extending from the top of said well to the armature of the top relay, a conductor connecting a normally open contact of each relay with the armature of the next lower relay in said series, a lead connecting a normally closed relay contact to ground through said operating Winding, a lead connecting a normally open relay contact to ground through said second winding, and a lead connecting a normally closed relay contact to ground through the solenoid of the associated vaive, a circuit for supplying a predetermined number of high voltage relay-operating electrical pulses to the top conductor, thereby to cause a preselected relay to move to its operating position, an ammeter and a switch connected in series in said circuit, a low voltage source, an ammeter and a switch connected in circuit therewith, and leads connecting the low voltage circuit to the circuit detined by ground and said top conductor.

6. In combination, tubing suspended in a well, a series of vertically-spaced valve units mounted on said tubing, each unit including a valve connecting the interior of the tubing with the exterior thereof, mechanism operatively connected to said valve to open and close same, and a f pulse-responsive device having two operating positions, each pulse incident upon said device causing it to shift from one operating position to the other operating position, said device being constructed and arranged to disable said mechanism in one operating position but not in the other operating position, said device further being constructed and arranged to deine a transmission path for pulses in a first of said operating positions but not in the second of said operating positions, means connecting the transmission paths of all of said devices in series, means for applying pulses to the uppermost device, and means for applying valve-operating power to the uppermost mechanism not disabled by its pulse-responsive device.

7. In combination, tubing suspended in a well, a series of vertically-spaced valve units mounted on said tubing, each unit including a valve connecting the interior of the tubing with the exterior thereof, mechanism operatively connected to said valve to open and close same, and a pulse-responsive device having two operating positions,

each pulse incident upon said device causing it to shift from one operating position to the other operating position, said device being constructed and arranged to disable said mechanism in one operating position but not in the other operating position, said device further being constructed and arranged to deline a transmission path for pulses in a rst of said operating positions but not in the second of said operating positions, means connecting the transmission paths of all of said devices in series, means for applying pulses to the uppermost device, means for applying valve-operating power to the uppermost mechanism not disabled by its pulse-responsive device, and means independent of said pulse applying means to cause all of said pulse-responsive devices to assume one of said two operating positions.

8. In combination, tubing suspended in a well, a series of vertically-spaced valve units mounted on said tubing, each unit including a valve connecting the interior of the tubing with the exterior thereof, mechanism operatively connected to said Valve to open and close same, and a pulse-responsive device having two operating positions, each pulse incident upon said device causing it to shift from one operating position to the other operating position, said device being constructed and arranged to disable said mechanism in one operating position but not in the other operating position, said device further being constructed and arranged to define a transmission path for pulses in a iirst of said operating positions but not in the second of said operating positions, means connecting the transmission paths of all of said devices in series, means for applying pulses to the uppermost device, whereby said pulses travel downwardly through `each successive unit which is in said tirst operating position and thereby selects the valve unit immediately below the lowermost successive unit for operation, and means for applying Cil 12. valve-operating power to said transmission path to operate the selected valve unit.

9. In combination, tubing suspended in a well, a series of vertically-spaced valve units mounted on said tubing, each unit including a valve connecting the interior of the tubing with the exterior thereof, mechanism operatively connectedv to said valve to open and close same, and a pulse-responsive device having two operating positions, each pulse incident upon said device causing it to shift from one operating position to the other operating position, said device being constructed and arranged to disable said mechanism in one operating position but not in the other operating position, said device further being constructed and arranged to define a transmission path for pulses in a tirst of said operating positions but not in the second of saidl operating positions, means connecting the transmission paths of all of said devices in series, means for applying pulses to the uppermost device, whereby said pulses travel downwardly through each successive unit in said tirst operating position and thereby selects the valve unit immediately below the lowermost successive unit for operation, means for applying valveoperating power to said transmission path to operate the selected valve unit, and means independent of said pulseapplying means to cause all of said pulse-responsive devices to assume predetermined operating positions.

l0. The combination, with casing disposed in a well, tubing mounted concentrically within said casing, and means for admitting uid under pressure to the interspace between said tubing and said casing, of a series of solenoid valves spaced vertically along said tubing, each valve connecting the interior of the tubing with the exterior thereof to regulate the ow of uid from said interspace into said tubing, and each valve being operated in a stepwise manner to progressively open said valve and then return it to its closed position, a series of relays operatively connected to the solenoids of the respective valves, each relay having an armature movable to an operating position and a non-operating position, a iirst winding arranged to effect movement of said armature to said operating position, a second winding arranged to move said armature to said non-operating position, contacts arranged to be opened and closed by movement of said armature, a source of relay operating pulses, a circuit including certain of said contacts, said first winding and said source arranged to energize said rst winding when the armature is in non-operating position, a circuit including others of said contacts, said second winding and said source arranged to energize said second winding when the armature is in operating position, a circuit including said source, and others of said contacts arranged to be closed when the relay is in non-operating position, said last-mentioned circuit being constructed to transmit relay operating pulses to the next lower relay in said series, and means for feeding valve-operating pulses through contacts of the uppermost relay in the operating position to the solenoid of the valve connected thereto.

ll. The combination, with casing disposed in a well, tubing mounted concentrically within said casing, and means for admitting tiuid under pressure to the interspace between said tubing and said casing, of a series of solenoid valves spaced vertically along said tubing, each valve connecting the interior of the tubing with the exterior thereof to regulate the flow of fluid from said interspace into said tubing, and each valve Vbeing operated in a stepwise manner to progressively open said valve and then return it to its closed position, a series of relays operatively connected to the solenoids of the respective valves, each relay having an armature movable to an operating position and a non-operating position, a tirst winding arranged to effect movement of 'said armature to said operating position, a second winding arranged to move said armature to said non-operating position, contacts arranged to be opened and closed by movement of said armature, a source of relayoperatingpulses, a circuit including certain of said contacts, said first winding and said source arranged to energize said tirst winding when the armature is in nonoperating position, a circuit including others of said contacts, said second winding and said source arranged to energize said second winding when the armature is in operating position, a circuit including said source, and others of said contacts arranged to be closed when the relay is in non-operating position and constructed to transmit relay operating pulses to the neXt lower relay in said series, means for feeding valve-operating pulses through contacts of the uppermost relay in the operating position to the solenoid of the valve connected thereto, a switch connected in said last-mentioned feeding means for momentarily changing the resistance thereof when said valve returns to its closed position, and a meter connected in circuit to said switch to detect said momentary change in resistance.

12. The combination, with casing disposed in a well, tubing mounted concentrically within said casing, and means for admitting uid under pressure to the interspace between said tubing and said casing, of a series of solenoid valves spaced vertically along said tubing, each valve connecting the interior of the tubing with the exterior thereof to regulate the ow of fluid from said interspace into said tubing, and each valve being operated in a stepwise manner to progressively open said valve and then return it to its closed position, a series of relays operatively connected to the solenoids of the respective valves, each relay having an armature movable to an operating position and a non-operating position, a rst winding arranged to eiect movement of said armature to said operating position, a second winding arranged to move said armature to said non-operating position, contacts arranged to be opened 14 and closed by movement of said armature, a source of relay operating pulses, a circuit including certain of said contacts, said first winding and said source arranged to energize said rst winding when the armature is in nonoperating position, a circuit including others of said contacts, said second winding and said source arranged to energize said second winding when the armature is in operating position, a circuit including said source, and others of said contacts arranged to be closed when the relay is in non-operating position and constructed to transmit relay operating pulses to the next lower relay in said series, means for feeding valve-operating pulses through contacts of the uppermost relay in the operating position to the solenoid of the valve connected thereto,

a switch connected in said last-mentioned feeding means for momentarily changing the resistance thereof when said valve returns to its closed position, a meter connected in circuit to said switch to detect said momentary change in resistance, and means for moving the armature of all of said relays to a non-operating position.

References Cimd in the le of this patent UNITED STATES PATENTS 1,339,844 Burchett May 11, 1920 1,827,765 Roebel Oct. 20, 1931 2,168,198 Frink Aug. 1, 1939 2,207,055 Goodling July 9, 1940 2,277,579 Burger Mar. 24, 1942 2,278,532 Crickmer Apr. 7, 1942 2,307,171 Tutton Ian. 5, 1943 2,368,104 Beltrami Jan. 30, 1945 

1. THE COMBINATION, WITH CASING DISPOSED IN A WELL, TUBING MOUNTED CONCENTRICALLY WITHIN SAID CASING, AND MEANS FOR ADMITTING FLUID UNDER PRESSURE TO THE INTERSPACE BETWEEN SAID TUBING AND SAID CASING, OF A SERIES OF SOLENOID VALVES SPACED VERTICALLY ALONG SAID TUBING, EACH VALVE CONNECTING THE INTERIOR OF THE TUBING WITH THE EXTERIOR THEREOF TO REGULATE THE FLOW OF FLUID FROM SAID INTERSPACE INTO SAID TUBING, AND EACH VALVE BEING SOLENOID OPERATED, A SERIES OF RELAYS, ONE FOR EACH VALVE, EACH RELAY INCLUDING AN ARMATURE, A SET OF NORMALLY CLOSED CONTACTS AND A SET OF NORMALLY OPEN CONTACTS ASSOCIATED WITH SAID ARMATURE, AN OPERATING WINDING FOR ATTRACTING SAID ARMATURE TO MOVE IT TO THE NON-OPERATING POSITION, A LATCH FOR HOLDING SAID ARMATURE IN ITS NON-OPERATING POSITION, AND A SECOND WINDING FOR RELEASING SAID LATCH, SAID TUBING CONSTITUTING A GROUND CONNECTION FOR THE ELECTRICAL CIRCUIT OF SAID RELAYS, A CONDUCTOR EXTENDING FROM THE TOP OF SAID WELL TO THE ARMATURE OF THE TOP RELAY, A CONDUCTOR CONNECTING A NORMALLY OPEN CONTACT OF EACH RELAY WITH THE ARMATURE OF THE NEXT LOWER RELAY IN SAID SERIES, A LEAD CONNECTING A NORMALLY CLOSED RELAY CONTACT TO GROUND THROUGH 